Crown for teeth.



J. L. BENSON.

Patented May 18, 1909.

2 SHEBTSSHEET 1.

J. Ill BENSON.

GROWN FOB. TEETH.

APPLIOATION FILED JUNE 13, 1908.

Patented May 18, 1909.

2 SHEETS-SHEET 2.

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UNITED STATES PATENT FFTQ.

JAMES LEE BENSON, OF WINNIPEG, MANITOBA, CANADA.

GROWN FOR TEETH.

To all whom it may concern:

Be it known that 1, James LEE BENSON, of the city of Vvmmpeg, 1n the Province of Specification of Letters Patent.

Application filed June 13, 1908.

Patented May 18, 1909. Serial no. 438,388

6 is a porcelain face secured to the crown and in order to better understand the advantage of the groove I will now describe Manitoba, Canada, have invented certain I the manner in which the porcelain is prenew and useful Improvements in Crowns for Teeth, of which the following is the specification.

My invention relates to improvements in crowns for teeth, particularly to the placing of porcelain or other such like material on the crown so that the artificial tooth may present a natural appearance and the object of the invention is to attach the porcelain facing to the base of the crown and the base to the tooth without the use of rivets or pins either between crown base and the tooth or between the facing and the crown base.

It consists essentially in forming a crown of gold or other desirable metal adapted to fit over the tooth having a cut-away portion in the face of the crown, a plate soldered within the crown to the back of the opening therein, a porcelain face for the tooth baked on the crown, such face being held to the tooth by the porcelain wedging between the inserted plate and the face of the crown, the arts being arranged and constructed as hereinafter more particularly explained.

Figure 1, is an enlarged perspective view of a crown with the porcelain face attached. Fig. 2, is a side elevation as in Fig. 1. Fig. 3, is a plan view as in Fig. 2. Fig. 4, is a vertical sectional view through the crown, the plate, and the porcelain, the section being taken in the plane denoted by the line X X Fig. 3. Fig. 5, is an inverted plan view of the crown and the porcelain face. Fig. 6, is a front elevation of the crown showing the manner in which the face is cut away. Fig. 7 is a sectional view of a modification.

In the drawings like numerals of reference indicate corresponding parts in each figure.

1 represents a crown formed from gold or other suitable metal in the usual manner, such crown being adapted to fit over that portion of the root of the tooth which remains in the mouth, to which it is firmly cemented. The front face of the crown is surrounded by portions of the crown.

l g I pared ;The porcelain as a powder is mixed to a paste with water and in paste form is applied to the face of the crown and shaped to the natural form of the tooth. It will be seen that as the paste is put on the crown it will squeeze into the groove. After the porcelain has been applied it is baked and in baking hardens and shrinks slightly. More of the porcelain is applied and it is again baked, this being repeated until the face presented is of the natural size. When the baking is finally finished the porcelain. face is firmly secured to the crown as it not only adheres to the plate and the crown, but it is also held by that part of the porcelain which is wedged between the plate and the crown. It will be seen that the porcelain face is not in the sli htest weakened and that it is protected at the bottom by the tip '7 of the crown.

If it be desired to have a partially gold and part porcelain face presented it is only necessary to make the opening 3 smaller and attach the porcelain portion of the face as first described. The gold portion of the face is formed on that portion of the face of the crown which remains intact.

An important advantage gained in the use of this form of crown is that in event of breakage it is unnecessary to remove the crown from the root of the tooth as the old porcelain face can be removed and a new one substituted, the new one having, however, to be mixed and set by chemicals.

In cases where it is impossible to use a crown, that is, where the root is too-far decayed, the pin already referred to which passes into the nerve opening could be used, and in this case the plate 4 would pass more nearly horizontal than vertical. The porcelain face would be applied as already described and the pin would pass through the plate into the porcelain within thecrou This arrangement is shown in Fig. 7, in

: which the substantially horizontal plate is cut away at 2 leaving an opening 3 which is lVithin the crown and somewhat away from the opening is soldered a metallic plate 4 which closes over the opening and leaves a groove 5 completely around the opening and between the plate and the face of the crown.

shown at 4 and the pin at 4 What I claim as my invention is:

1. The process of preparing an artificial tooth which consists in forming a crown with a partially open forward face and in forming on the crown a porcelain tooth face which is held to the crown by the porcelain setting with a portion of it overlapping on inner face of the crown and between the the inner face of the crown. plate and the crown, as and for the purpose 2. The process of preparing an artificial specified. tooth which consists in forming a crown Signed at -Winnipeg, in the Province of a with a partially 1rppen forward film; in attach- Manitoba, this 21st day of May, 1908. ing a ate to t e interior wa 0 the crown l m T sonieiir hat back from the opening; and in l JAB/lbs LEE forming on the crown a porcelain tooth face WVitnesses: which is held to the crown by the porcelain GERALD S. ROXBURGH, 10 setting with a portion of it overlapping the M. A. SOMERVILLE. 

